Leptonyxa Reitter 1876

Body size: about 7.0 mm. Body shape flat. Gular sutures wide, convergent at apex. Frontoclypeal suture absent. Frons: longitudinal groove or depression absent. Cranium ventrally: tufts of long setae at sides present. Submentum: ctenidium absent. Antennal groove absent. Eyes: size large, lateral. Eyes number: two. Epicranial acumination absent. Lacinial hooks absent. Galea: shape elongate. Galea: ciliate setae absent. Mediostipes-Lacinia fused together. Palpifer: outer edge even. Mandibular apical teeth number: two, horizontally situated. Mola absent. Penicillus (at base) absent. Pubescence above mola or cutting edge present. Ventral furrow present. Basal notch shallow or absent. Labrum-Cranium fused. Epipharyngial sclerite absent. Lateral tormal process: projection projection not developed (all remaining). Ligula: ciliate setae absent. Ligula rigid, not retroflexed, weakly emarginate. Hypopharyngeal sclerite absent. Antenna 10-segmented. Antennal club weakly asymmetrical, sensorial fields absent. Front coxal cavities externally open, internally open. Pronotum transverse. Prepectus present. Middle coxal cavities open. Elytra: long hairs absent. Epipleuron moderate. Elytral interlocking mechanism absent, carinae conspicuous. Elytral punctation regular, scales absent. Wing: radial cell moved down, often small, wedge cell absent, cross vein MP3-4 absent, cross vein AA1+2-3+4 absent. Front tibiae: spines along side moderate. Hooked spur present. Claws: denticle absent. Parasternites number along ventrites III–VII: absent. Spiculum gastrale absent. Tegmen composed of three parts. Coxitae undivided.

Tropical South America: Bolivia, Colombia, Brazil.